And arthur b



UNITED STATES PATENT OFFICE.

JOSEPH A. GARDE, OF \VATERBURY, CONNECTICUT, AND ARTHUR l3. BRUNELL, OF WORCESTER, MASSACHUSETTS, ASSIGNORS TO THE OARRARA ELECTRO-MARBLEIZING COMPANY, OF NEW JERSEY.

METHOD OF METAL-COLORING.

SPECIFICATION forming part of Letters Patent No. 575,678, dated January 19, 1897.

Application filed March 24, 1896.

To all whom it may concern.-

Be it known that we, J osnrn A. GARDE, residing at the city of Waterbury, in the county of New Haven and State of Connecticut, and ARTHUR B. BRUNELL, residing at the city of WVorcester, in the county of Worcester and State of Massachusetts, citizens of the United States, have invented certain new and useful Improvements in Methods of Metal-Colorin g and We do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Our invention relates to metalcoloring, such as is accomplished by chemical or electrochemical agencies; and it consists of a method whereby silver may be so colored as to resemble a piece of marble, the various colors or shades of color being disposed upon the surface of the metal in irregular and varied cloud-like patches, which present to the eye endless effects of form and outline.

The invention also consists in an article that is produced by the said method.

The invention will be more fully disclosed in the detailed description of the specification, and its essential features or steps pointed out in the claims. I

The operation which. are are about to describe we designate marbleizingf The silver which is to be marbleized may be either in the form of a solid body or of a plating which has been deposited upon a body by electrolytic action or in any other suitable manner.

The marblcizing is produced by the action of a mixture of acids, organic or inorganic, or of an acid and an alkali, upon the silver. The mixture is sprinkled upon the surface of the silver by means of a brush, which has been dipped in the same, or is applied in any other suitable manner. The color of those parts of the surface upon which the drops of the mixture fall will be changed as soon as the chemical action takes place, and the areas affected in this way will be gradually enlarged as the mixture spreads upon the surface of the silver. The shades of color within these areas will vary and thus add to the general efiectof the different colors which the mixtures have already produced.

The mixtures employed may be sulfuric acid and nitric acid, or sulfuric acid, water, and nitrate of soda or potash, or sulfuric acid, nitrate of soda, and muriatic acid.

The mixture of sulfuric acid and nitric acid produces various brown tints upon the surface of the silver.

The mixture. of sulfuric acid, Water, and nitrate of soda or potash is the equivalent of the mixture of sulfuric and nitric acids, since nitric acid is set free when these chem ical compounds are commingled.

The mixture of sulfuric acid, nitrate of soda, and muria'tic acid produces,'inaddition to the colors created by the mixtures above named, an iridescent blue.

If the various mixtures are applied directly to the silver, the rapid chemical action is likely to etch the same and produce an undesirable roughness upon its surface, although if the mixtures are weak or are quickly removed or neutralized the etching may be avoided. If the plating is thin, the mixtures will not only etch the surface, but will destroy the plating and expose the surface of the underlying metal.

In order to avoid the necessity of heavily plating the body or of haste in removing the mixtures for the purpose of preventing etching of the surface of the silver, we dip the silver-plated body in a preliminary bath consistin g of an alkaline salt or a simple alkaline solution. This bath may be cyanid of copper, or water, cyanid of potassium, and carbonate of copper, or potash or soda-lye, or cyanids of copper and potassium.

hen the silver or silver-plated body is dipped in a bath of cyanid of copper, it will be covered with a thin film of this solution. The acid of the applied mixture combines with the copper of the solution and is partly used up before acting upon the silver. After it has eaten through the said film it is nearly exhausted, and hence has power to only faintly streak the silver.

A bath of water, cyanid of potassium, and carbonate .of copper is the equivalent of a bath of cyanid of copper, since cyanid of copper is formed by the chemical reactions which are due to the mixing of these cc 1- pounds. Copper is not soluble 1n water and will precipitate if not held in the solution of a soluble chemical combination, and hence a bath of the character just referred to is necessary to the equal distribution of copper all over the surface of the silver.

The simple alkaline solution which we use is potash or soda-lye. This solution neutralizes to a certain extent the action of the acid and develops dark streaks, which render the effect more pronounced than does the cyanid of copper. The dark streaks may also be produced by applying the alkaline solution after the cyanid of copper and the mixture have been used, or even after the silver or silver-plated body has been subjected to the action of the mixture alone.

The bath ofv the cyanids of copper and po- Iassium combines the effects of the salt and the alkaline solutions.

We do not desire to be limited to the use of a preliminary bath, because good effects can be produced by the action of the mixtur s alone. In practice, however. we prefer to employ said bath, because its use leads to the production of better results.

finstead of. or in addition to, dark and light spot's'red streaks are desired, the article after being treatedwith the acids is placed in an electrolytic bath, consisting of a hot solution of carbonate of copper, five pennyweights; cyanid of potassium,six pennyweights; water, one gallon; carbonate of soda, five ounces; and carbon ate of ammonia, five ounces. The

metal being connected to the negative pole and copper plates being hung on the positive p le, as is usual in electroplating, red streaks will appear upon the article after the current has been passing for a few seconds.

Various causes will affect theappearance of the marbleized surface. The proportions and strengths of the acids, the quantity of water in the various solutions, the temperatures of and the time of immersion in the respective baths, and the strength of the electric current when one has been employedal tend to vary the results attains 1.

The marbleizing having been completed, the article must be protected from atmospheric influences, so that the marbleized surface may remain unehanged. For this purpose any suitable lacquer or transparent coatmg may be employed. If it were not for the atmospheric infiuences,the lacquer or'coating might be omitted altogether. The lacquer may be applied directly after the article has been washed, without waiting for the water to evaporate.

It is to be understood that the operation of silvering the surface of a body preparatory to marbleizing the same is only the ordinary process of silver-plating, and has nothing to do with the process which we term marble- 12mg. The only reason for working upon silver-plated bodies lies in the direction of economy, or is based upon the desirability of marbleizing the surface of a metal which is to be used for a particular purpose, because of some property or properties which it possesses.

It will be seen from the above description that the essential part of the operation of marbleizing is the sprinkling of the surface of a solid-silver or silver-plated body, with a mixture of chemical agents which act upon the surface in such a way as to produce the irregular, varied, and colored cloud like patches to which allusion has been made; that the efiect may be modified if, when the acid is applied, there is already upon the surface of the silver the solution of a metallic salt, such as has been described,.and that a great contrast between the mottled and plain parts of the surface may be produced by subjecting the article to the action of an alkaline solution before or after the acids have done their Work.

The electrolyte and the alkali are used hot, so as to facilitate the chemical reactions.

The body must be washed after it is taken from the silver-plating bath and also before the lacquer is applied, so that the action of the preliminary bath may not be interfered with and the lacquer affected in any way by the chemicals.

The following recipes for marbleizing will give a clear idea of the various ways in which the process may be performed:

No. 1. The body is taken from the silver plating bath, washed in Water, dipped in'a solution of water, cyanid of potassium, and carbonate of copper, and without washing immediately sprinkled wit-h an acid. combination of sulfuric acid, five parts, and nitric acid, one part, mixed together. The article is then washed and placed in a solution of water, one gallon, five ounces of carbonate of soda, five ounces of carbonate of ammonia, five pennyweights of carbonate of copper, and six pen nyweig'hts of cyanid of potassium. The solution is used hot and a strong electric current is employed. The .article being treated is the cathode. The article is taken out, Washed off, and enameled while wet.

No. 2. Conduct operation as in recipe No. 1 until the metal is mottled by the acid. Then wash 0E and dip in a hot solution of potash or soda-lye and water. Then wash and enamel as in recipe No. 1.

No. 3. Conduct operation as in recipe No. 1, using instead of the acid mixture sulfuric acid,five ounces; water, three ounces; nitrate of potash, two ounces, and continue the operation precisely as in No. 1 or No. 2.

No. 4- Take work from silver-plating solution and put acid mixture as in recipe No. 1 or No. 3 directly on the silver without dipping in the cyanid ofv potassium and copper, as in example No. 1.

No. 5. Take work from silver-plating solution, wash in water and dip in a hot solution of potash or soda-lye. rectly on withoutwashing off the alkali and wash off the acid mixture and enamel as before.

No. 6. Conduct operation as in recipe No. 1, using instead of the acid, sulfuric acid, fifteen parts; nitrate of soda, five parts, and niuriatic acid, one part. Develop as in recipe No. 1 or No. 2.

No. 7. Conduct operation as in recipe No. 1 or No. 2, using in place of the acid mixture the following acid mixture sulfuric acid, one pound, nitrate of potash or soda, four ounces, using as a preliminary bath four ounces saturated solution of cyanids of copper and potassium. Develop as in recipe No. l and enamel.

From the above recipes it is evident that instead of mixtures of acids mixtures of acids and salts may be used, the weaker acids being set free by the stronger ones, and the mixture thus becoming a mixture of two acids.

Sulfuric acid, if used alone, will not appreciably affect the silver, and nitric acid, if not mixed with sulfuric acid, will act upon the silver with such vigor as to spoil the work. If nitric acid is applied to the surface of a silver-plated body, the silver will be removed and a black and unsightly blotch will take its place. A mixture of the two acids, however, has a very different effect, the nitric acid appearing to aid the sulfuric acid in forming a film of argentic sulfate. As this sulfate is only formed upon certain areas of the surface and as the different parts of the film within these areas are of various shades of color the completed articles have the appearance of pieces of marble. These articles differ from each other just as pieces of marble differ, and in many instances cannot be distinguished from genuine marble.

Of course these examples set no limits to the number of acids or of acid combinations used, as skill and experience will lead to the use of combinations of different qualities, producing different effects, according to taste and fashion.

\Ve are aware of the various oxidizing and etching processes which have been employed in the ornamentation of metallic surfaces and of the fact that metals have been colored by chemical actions.

Our invention does notinclude the so-called oxidation of brass which is caused by the action of nitric acid, nor does it include etching of any kind, and especially that kind which is due to the action of sulfuric and nitric acids upon brass; nor does our invention include the use of fumes arising from baths in which ametal has been dissolved. It is confined to the formation by chemical agencies of thin and variegated films upon the surface of a silver or silver-plated body. It is limited to chemical agents comprising a Put acid mixture di-l mixture which contains at least one acid and to the application of this mixture in such a way as to avoid anything like uniformity of coloring upon the entire surface of the work.

Having thus fully described our invention, what we claim, and desire to secure by Letters Patent of the United States, is

l. The method of marbleizing metal which consists in applying to unequal and irregularlyshaped parts of the surface of a silver or a silver-plated body chemical mixtures containing two acids, or an acid and an alkali, and in removing or neutralizing the acids after the marbleizing has been eifected and before the surface has been etched, substantially as described.

2. The method of marbleizin g metal which consists in sprinkling upon the surface of a silver or a silver-plated body chemical mixtures containing two acids, or an acid and an alkali, and in removing or neutralizing the acids after the marbleizing has been effected and before the surface has been etched, substantially as described.

3. The method of marbleizing metal which consists in dipping a silver or a silver-plated body in a preliminary neutralizing-bath, applying a mixture containing two acids or an acid and an alkali to the surface, and removing or neutralizing the mixture, substantially as described.

i. The method of marbleizing metal which consists in dipping a silver or a silver-plated article in a preliminary bath consisting of a metallic salt or an alkali, sprinkling a mixture of sulfuric acid and nitric acid, or sulfuric acid and nitrate of soda or potash upon the surface of the article, and removing or neutralizing the mixture, substantially as described.

5. The method of marbleizing metal which consists in subjecting unequal and irregularly-shaped parts of the surface of a silver or a silver-plated body to chemical action,whereby the color of such parts will be changed, and electrically depositing upon the same streaks of copper so as to produce red veins of color, substantially as described.

6. As an article of manufacture, a silver or silver-plated body presenting a marbleized or variegated surface of various colors, such body having irregular and unequal parts of its integral surface film composed of portions which have different chemical constitutions and which are variously colored.

In testimony whereof we affix our signatures in the presence of witnesses.

JOSEPH A. GARDE. v ARTHUR B. BRUNELL. lVitn esses:

JOHN WM. DONALD, ALFRED J. NoLFF, B. F. PIERSON, E. E. DE LORME.

IIO 

